Infernalis has just been released a couple of weeks ago and I have to admit that I am really impressed of the work that has been done. So I am going to present you 5 really handy things that came out with this new release.

1. Use units to create an image and for benchmark commands

Prior to this, the default unit was MB so we had to write the image size in consequence.

$ rbd create a -s 1G

2. Space used by an image

Since images are sparse and that discard is available for some virtualization storage controllers it is nice to have the ability to track the space used by an image. Obviously using object-map is highly recommend here, as it will speed up the calculation time.

$ rbd du a
warning: fast-diff map is not enabled for a. operation may be slow.
NAME PROVISIONED USED
a          1024M    0

$ rbd -p rbd bench-write a --io-size 4096 --io-threads 1 --io-total 4096 --io-pattern rand
bench-write  io_size 4096 io_threads 1 bytes 4096 pattern rand
  SEC       OPS   OPS/SEC   BYTES/SEC
elapsed:     0  ops:        1  ops/sec:    83.42  bytes/sec: 341671.93

$ rbd du a
warning: fast-diff map is not enabled for a. operation may be slow.
NAME PROVISIONED  USED
a          1024M 4096k

3. OSD performance analyser

A new command that will connect to the daemon’s socket and show some statistics.

$ ceph daemonperf osd.1
---objecter--- -----------osd-----------
writ read actv|recop rd   wr   lat  ops |
  0    0    0 |   0    0   53k 339   13
  0    0    0 |   0    0  753k 516  180
  0    0    0 |   0    0  843k 149  206
  0    0    0 |   0    0  507k  34  123
  0    0    0 |   0    0  630k  45  150
  0    0    0 |   0    0  626k  33  149
  0    0    0 |   0    0  573k  57  138
  0    0    0 |   0    0  172k  49   42
  0    0    0 |   0    0    0    0    0
  0    0    0 |   0    0    0    0    0

4. Enable and disable image feature on the fly

Quick example on how to enable object map after the image creation.

$ rbd create a -s 1G --image-feature exclusive-lock
$ rbd info a
rbd image 'a':
        size 1024 MB in 256 objects
        order 22 (4096 kB objects)
        block_name_prefix: rbd_data.856d51f8ceac
        format: 2
        features: exclusive-lock
        flags:

$ rbd feature enable a object-map

5. Default new images to format 2

Thanks to this, we do not need to specify the format during the image creation, nor add a new line into your ceph.conf.

Enjoy!